ProjectSummary Researchersgenerallyagreethathumanemotionscorrespondtotheexecutionofanumberofcomputationsby thenervoussystem.But,thereisstrongdisagreementonwhatthesecomputationsare.Onehighlycontentious pointistheperceptionofemotionthroughfacialexpressions.Thatis,whicharetheemotionsignalsproduced byasenderthatarevisuallyrecognizedbyanobserver?Theoverarchinggoalofourresearchistoidentifythese signalsandspecifytheformanddimensionsofthecomputationalmodeloftheirvisualrecognition.Ourgeneral hypothesisisthatthehumanvisualsystemsolvestheinverseproblemofproduction.Inthefirstfiveyearsof funding, we have studied the hypothesis that consistent and differential facial muscle actions (called, action unitesorAUs)areasubsetofthesecomputationsexecutedbythenervoussystem.Thatis,whenexperiencing the same emotion, identical AUs are used by all people. Additionally, these AU activations are differential betweenemotions.Thus,ourgenerallyhypothesisstatesthatthegoalofthevisualsystemistoidentifywhich AUs are present in an image of a face. To date, we have completed several computational, behavioral and imaging studies favoring this hypothesis. These studies identified a previously unknown set emotive signals calledcompoundfacialexpressionsofemotion.However,theseresultsweregivenbyananalysisofposedfacial expressionsofemotionfilmedincontrolledconditionsinthelaboratory.Thefirstspecificaimofthisrenewalis to assess the validity of these results on facial expressions seen outside the laboratory (called ?in the wild?). Sincetheheterogeneityofspontaneousfacialexpressionsobservedoutsideofthelabislargerthanthoseseen inposedexpressions,wehypothesizethatfacialexpressionsinthewildcommunicateanevenlargernumberof emotionsthanthosepreviouslyidentified.Also,theseresultsstudythecomputationsexecutedbythenervous system that yield consistent and differential movements of one?s facial muscles only. In our second aim, we hypothesizethatthecomputationsexecutedbythenervoussystemalsoinvolvechangesinbloodflow,e.g.,by increasingbloodflowinthefacewhenexpressinganger.Specifically,wehypothesizethatthesechangesare consistentwithinanddifferentialbetweenemotions.Thus,ourgeneralhypothesisimpliesthatthevisualsystem mustidentifythesefacialcolorchanges.Wewillalsotestthealternativehypothesisthatfacialcolorisusedto communicateotheremotivevariables,e.g.,valenceandarousal.Ourthirdandfinalaimwillexaminetheneural mechanismsassociatedtothecomputationsstudiedintheprevioustwoaims.Ourstudiesaretimely,because alackofunderstandingofthecomputationsofemotionposesacriticalbarriertoprogressinbasicandclinical research.Specifically,researchersaredividedonwhetheremotioncategoriesidentifiedinthelaboratoryalso exist in the wild, there is a poor understanding of which emotion signals are communicated through facial expressions,anditisunclearwhichneuralmechanismsareassociatedwiththesecomputations.